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SI S



David-

Your comments on writing the organic reactions were very helpful. We now calculate exactly what we want.

Here's another problem. I want to know how the SI of S (native sulfur) decreases along the SO4 - H2S or HSO4 - H2S boundary (whether stable or metastable) as pH increases. I defined a phase to fix the SO4-H2S activities to be equal, but when I change the pH with a REACTION, I move off the booundary. I haven't been able to figure out how to stay on the boundary and fix the pH at the same time.

Is this possible? Here is my file:

DATABASE llnl.dat
TITLE	sulfur SI
PHASES
	fix_S
	H2O + SO4-2 = H2S
	-no_check
	-log_k	0
SELECTED_OUTPUT
	-file		int_S.sel
	-reset		false
	-ph		true
	-totals		S(-2) S(6)
	-activities	H2S SO4-2
	-saturation_indices	S
SOLUTION 1
	units		mol/kgw
	temp		25
	S		0.1
	pH		1	fix_S
REACTION
	NaOH
	0.1 0.2 0.21 0.22 0.23
END

We think this decrease in S activity is the clue to understanding TSR. At least that's what we think at the moment.

Thanks.

Greg.


Prof. Emeritus G.M. Anderson Department of Geology 22 Russell St. University of Toronto Toronto M5S 3B1 Canada

Fax;		416-978-3938
Dep't phone:	416-978-3021
My phone:	416-978-2062



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